Plumber Opportunity?

I have posted previously on my son's house he just bought which had the hot/cold reversed on the hot water heater, no pressure reducing valve, and an expansion tank that had failed. We replaced the TP valve on the water heater over Christmas because it was dripping. His house pressure was at 90 PSI.

Well, his hot water heater failed this week, brown water that never cleared even after flushing. So, he had a local plumbing company come in and replace the water heater, add a pressure reducing valve, and replace the expansion tank.

The outcome was that the water heater drip tube had not been switched so the hot and cold reversed was bad. The anode rod was just a wire so completely depleted. The expansion tank was on the hot side. The plumber fix both of these problems. My son ask about setting the expansion tank pressure equal to the house pressure and the plumber basically said it was pre-charged and fine. The plumber set the PRV to 70 PSI. This weekend my son set the PRV to 60 PSI and set the expansion tank to 60 PSI also, it was preset to 40 PSI.

So, my question to all plumbers why do you not offer a yearly test of your expansion tank and PRV? I always get brochures in the mail about a yearly checkup for my heating/cooling system. But, in my area nothing on the plumbing side. It would seem if folks would do this alot of expansion tanks and PRV valves would be fixed.

90% of customers are not going to spend the $ 145.00 dollar service call to have a $ 50.00 dollar expansion tank checked are they?

Cost

Well, ok $145 seems steep. The heating/cooling guys have deals in the $59-89 dollar range. And if something has to be done, they subtract the fee. Also, in my area lots of companies are doing heating/cooling and plumbing. So, add the plumbing check to the heating and cooling maintenance.

I have ONE price regardless of what I do, therefore testing a PRV or expansion tank would cost more than they are worth, especially if it were done yearly and the devices lasted MANY years before failing. The plumber was correct, since regardless of the initial pressure, the tank will stabilize at the house's pressure as soon as the water is turned on, although setting both of them approximately the same will give SLIGHTLY better performance, but then setting it slightly higher than the house pressure would do even better, since the amount of air in the tank, when the water is on, determines its overall effectiveness.

Confused

So, if my house water pressure is 45 PSI with a pressure reducing valve(closed system) and I set the expansion tank to 50 PSI, won't the pressure now rise to 50 PSI(water heater heating) before the bladder can do its thing?

Not sure how it works better because the presssure in the expansion tank is higher than the normal PRV pressure.

I also assumed that setting the expansion tank pressure equal to the house pressure was to reduce the amount the bladder has to stretch over time and makes it last longer.

The expansion tank is to minimize pressure buildup, it does NOT prevent it. The pressure is going to increase somewhat no matter what the tank is set for. The bladder does NOT stretch, it "folds"as the pressure increases or decreases. When the tank is initially charged the bladder fills the tank. As water enters the tank the bladder begins to fold an retract into the tank. This process causes the air pressure to equalize with the system's water pressure any time the air pressure is less than the system pressure. When it is greater, then it doesn't act to reduce the pressure until the expansion raises the pressure to that point, but as long as that pressure is around 80 psi, the system still does not go into the "excessive pressure" range. But that pressure setting would cause the LEAST flexing of the tank's bladder.